Metathesis is generally thought of as the interchange of radicals between two compounds during a chemical reaction. There are several varieties of metathesis reactions, such as ring opening metathesis, acyclic diene metathesis, ring closing metathesis and cross metathesis. These reactions, however, have had limited success with the metathesis of functionalized olefins.
Methods for the production of polyolefins with end-functionalized groups are typically multi-step processes that often create unwanted by-products and waste of reactants and energy.
R. T. Mathers and G. W. Coates Chem. Commun. 2004, 422-423 disclose examples of using cross-metathesis to functionalize polyolefins containing pendant vinyl groups to form polar-functionalized products with a graft-type structure.
D. Astruc et al. J. Am. Chem. Soc. 2008, 130, 1495-1506, and D. Astruc et al. Angew. Chem. Int. Ed. 2005, 44, 7399-7404 disclose examples of using cross metathesis to functionalize non-polymeric molecules containing vinyl groups.
For reviews of methods to form end-functionalized polyolefins, see: (a) S. B. Amin and T. J. Marks Angew. Chem. Int. Ed. 2008, 47, 2006-2025; (b) T. C. Chung Prog. Polym. Sci. 2002, 27, 39-85; (c) R. G. Lopez, F. D'Agosto, C. Boisson Prog. Polym. Sci. 2007, 32, 419-454.
U.S. Ser. No. 12/487,739, filed Jun. 19, 2009 discloses certain vinyl terminated oligomers and polymers that are functionalized for use in lubricant applications.
U.S. Ser. No. 12/143,663, filed on Jun. 20, 2008 discloses certain vinyl terminated oligomers and polymers that are functionalized in U.S. Ser. No. 12/487,739, filed Jun. 19, 2009.
Additional references of interest include: U.S. Pat. No. 4,988,764.
Thus, there is a need to develop a means to provide functionalized polyolefins (particularly end-functionalized) by metathesis reactions, particularly reactions with good conversion, preferably under mild reaction conditions is a minimal number of steps. There is also a need for a single reaction type that allows for a variety of functional groups to be added to polyolefins in an economical manner. The instant invention's use of olefin alkene metathesis to introduce functional groups is both a commercially economical and an “atom-economical” route to end functionalized polyolefins.
This invention further provides vinyl-terminated polyolefins that react with functionalized alkenes in the presence of a metathesis catalyst to form polar end-functionalized polyolefins.
End-functionalized polyolefins that feature a chemically reactive or polar end group are of interest for use in a broad range of applications as compatibilizers, tie-layer modifiers, surfactants, and surface modifiers. Herein is described a novel method for their production by the metathesis of vinyl-terminated polyolefins with functionalized alkenes. This method is useful in a range of polyolefins, including isotactic polypropylene (iPP), atactic polypropylene (aPP), ethylene propylene copolymer (EP), and polyethylene (PE).